1. Field of the Invention
The present invention relates to a dart for use in the game of darts, a sport in which arrow-like projectiles called darts are thrown at a target called a dartboard that is mounted on a wall or the like so that players can compete for the highest score.
2. Description of the Related Art
A dart is constructed by connecting component parts including, in order from the front, a pointed tip, a barrel, a shaft, and a flight. The tip at the front end is the part which hits the target. In the case of a hard dart, the tip is made of metal. In the case of a soft dart, the tip is made of plastic. The barrel serves as the body of the dart. When a player throws a dart, the player usually holds the barrel. The shaft, being the part to which the flight is attached, has a large effect on the stability of the dart while in flight.
Examples of conventional darts include darts disclosed in Japanese Utility Model Registration Application No. 3118732, Japanese Unexamined Patent Application Publication No. 2008-093153, and Japanese Unexamined Patent Application Publication No. 2008-142399.
In a conventional dart, the shaft and the flight are connected to each other by inserting the fins of the flight in slits formed in the shaft. This being the case, the slits are formed in the shaft in a cruciform arrangement as viewed in a plane perpendicular to the axial direction, the four fins of the flight being spaced at angular intervals of 90° about the axis so as to impart the dart with a cruciform profile as viewed in a plane perpendicular to the axial direction.
The shaft and the flight are formed using polypropylene (PP) or the like as the material. Since the thickness of the fins of the flight is very thin, being about 0.3 mm to 0.5 mm, the fins might for example be manufactured from four sheets of plastic film that each form one side of a pair of facing surfaces of neighboring fins.
Because the conventional dart described above is manufactured by a method in which the front end of the flight is inserted into slits in the shaft, a stepped region is inevitably formed at the boundary region where the shaft and the flight are mutually connected.
Generally, in a darts game, there is a case that, in a state where a dart thrown first hits the dartboard, the next dart is thrown and, sometimes, the next dart hits the dart already stuck in the dartboard. In a case where a front end of the tip hits the stepped region in the boundary between the shaft and the flight, a large stress is applied to both of the darts by the collision. When such a collision is repeated, the darts may be broken due to fatigue. In particular, because the portion at the boundary between the shaft and the flight is made narrow by presence of the four slits in the shaft, this portion is easily broken.
This is particularly true in the case of a hard dart, which might have a tip made of steel or other metal. In the event that a dart already stuck in the dartboard is hit from behind by such a dart, a very large stress will be applied to the stepped region in the boundary between the shaft and the flight, and there is the possibility that the dart will be broken easily. When a dart is broken due to collision as described above, this will of course negatively impact the player involved from an economic viewpoint.